The excess molar enthalpies, H-m(E), for methanol + 2-heptanone, 3-heptanone, and 4-heptanone have been measured as a function of mole fraction at 298.15 and 323.15 K by means of an isothermal now calorimeter. Values for H-m(E) are endothermic with a maximum value occurring at a mole fraction close to 0.5. The temperature effect on the excess enthalpy values is important. Maximum values at 298.15 K range from 725 to 744 J.mol(-1). Maximum values at 323.15 K range from 908 to 955 J.mol(-1). The position of the ketone group has little effect on the measured H-m(E).